hello, I'm making the preamp in question because I want to match it to the final stereo ready (aleph mini version of 10W single end);
looking at the circuit, I noticed the presence of a trimmer 2K, so I ask what is its setting (I guess this is for the bias current for proper operation of the differential);
two more questions:
Which property should have the electrical power transformer (the secondary output and power?)
what value of potentiometer 4 sections I use to create the volume control and where to enter (entry or output?)
thank you very much for your important help.

hello, I'm making the preamp in question because I want to match it to the final stereo ready (aleph mini version of 10W single end);
looking at the circuit, I noticed the presence of a trimmer 2K, so I ask what is its setting (I guess this is for the bias current for proper operation of the differential);
two more questions:
Which property should have the electrical power transformer (the secondary output and power?)
what value of potentiometer 4 sections I use to create the volume control and where to enter (entry or output?)
thank you very much for your important help.

hello.
for the transformer. you can use a 2x30V 160VA with secondarys conected in series. the 2k pot, isn't that the secondary volum pots?

hello.
for the transformer. you can use a 2x30V 160VA with secondarys conected in series. the 2k pot, isn't that the secondary volum pots?

160VA

Are you sure of this information?
surfing the net, I found the site KK-PCB, where I saw the power supply for aleph P1.7;
60Volt 50VA transformer is indicated for both channel,,,this indication is correct?

trimmer 2K is on the branch connecting the differential, I need to know how to make its regulation, that is, which parameter should I refer?
if I understand it, reading the manual of the great Nelson Pass, the volume control must be placed on the input of the preamplifier, using a binary system to relay, I wonder if you can use a simple potentiometer four sections, and if so what value?

I used an 80 VA toroid with 60 VAC secondaries on my Aleph P 1.7. Fifty VA is purportedly the norm, though I've heard that 30 VA is more than adequate.

The attenuator should have very low impedance -- 1k or 2k works well -- and should precede the preamp.

Regards,
Scott

Then I can use a transformer with a secondary 60V 50VA x,,,
I have an ALPS potentiometer 10K x 4 sections, I can use it by inserting it between the input and the preamp and the same fine-tune the gain using the trimmers from 2K that I have already put on board the pcb's?
thanks so much for your interest